1. Field of the Invention
The present invention relates to an ink jet head and an ink jet printer.
2. Description of the Related Art
Conventionally, there are known ink jet printers using such a method as to move an ink jet head having a plurality of nozzles in a predetermined scanning direction while jetting an ink or inks from the plurality of nozzles toward a recording medium to print images and the like. Further, as a printing operation of the ink jet printers using this method, there is known a bidirectional print, that is, the ink is jetted to print the images and the like respectively on both occasions that the ink jet head moves in one orientation of the scanning direction and moves in the other orientation of the scanning direction. Further, throughout the present specification, when such a bidirectional print is carried out, the term “forward moving” is used to refer to the moving of the ink jet head in one predetermined orientation, whereas the term “backward moving” is used to refer to the moving of the ink jet head in the opposite orientation from that in the forward moving.
In the bidirectional print mentioned above, the ink jet head jets the ink in both the forward moving and the backward moving. Therefore, there is an advantage for obtaining high print speed. However, when the ink jet head is a color ink jet head or the like configured to jet a plurality of types of inks, then the order of jetting the plurality of types of inks (the ink landing order) differs between the forward moving and the backward moving, thereby resulting in a decrease in image quality. In this regard, in order to equalize the order of jetting the plurality of types of inks between the forward moving and the backward moving, there are conventionally known ink jet heads having such a configuration as to arrange a plurality of types of nozzle rows separately on the left and on the right to respectively jet the plurality of types of inks.
For example, there are known ink jet heads which jet four color inks of black (K), cyan (C), magenta (M), and yellow (Y), and which have two nozzle rows for one color ink. Further, regarding the two nozzle rows for each color, the position of each nozzle of one of the two nozzle rows in the nozzle row direction is shifted with respect to the position of one of nozzle of the other of the two nozzle rows. Further, regarding the nozzle row direction, the position of each nozzle of one of the two nozzle rows for one color is coincide with the position of each nozzle of one of the two nozzle rows for another color. Further, regarding the nozzle row direction, the position of each nozzle of the other of the two nozzle rows for one color is coincide with the position of each nozzle of the other of the two nozzle rows for another color.
The total eight nozzle rows for jetting the four color inks are arranged symmetrically according to the scanning direction. In particular, the two nozzle rows for yellow are arranged adjacently in the center according to the scanning direction. Then, with respect to the above two nozzle rows for yellow, outwardly according to the scanning direction, there are arranged, in the following order, the two nozzle rows for magenta, the two nozzle rows for cyan, and the two nozzle rows for black. That is, from one side to the other side in the scanning direction, the eight nozzle rows are aligned in the order of “K”, “C”, “M”, “Y”, “Y”, “M”, “C”, and “K”. By arranging the nozzle rows in this manner, the inks are jetted in the same order between the forward moving and the backward moving of the ink jet head for the bidirectional print.